Tobacco varieties bring their own management constraints

By Chris Bickers, Contributing Writer

Tue, 2012-09-18 06:43

• Two fairly new varieties are dominating their respective types. NC 196 (flue-cured) and KT 209 (burley) have become just about the most popular varieties in just a few years. Both produce good yield and quality. In addition, both feature very good black-shank resistance.

• Their widespread adoption indicates growers believe that controlling black shank is a key factor in a good harvest and cure.

As the 2012 tobacco crop began its trip to market in earnest during August, growers were reminded of the benefits of picking the right variety for their conditions.

Two fairly new varieties are dominating their respective types. NC 196 (flue-cured) and KT 209 (burley) have become just about the most popular varieties in just a few years. Both produce good yield and quality. In addition, both feature very good black-shank resistance.

Their widespread adoption indicates growers believe that controlling black shank is a key factor in a good harvest and cure.

One who thinks that way is Steve Nelms of Louisburg, N.C. He planted his whole crop in NC 196.

“It is medium in black-shank resistance, and it did very well for us last year,” he said. On the one farm where he knows he has black shank, he also uses Ridomil to control the disease.

Nelms irrigates most of his tobacco, but he has one farm he can't irrigate. There may be a yield consequence from growing dryland this season, but Nelms thought there might be one benefit. “That un-irrigated tobacco will 'wait' for us at the end of the season, giving us further flexibility in harvesting late,” he said.

Holding ability

Nelms' neighbor down the road in Bunn, N.C., Steve Mitchell, planted 90 percent of his crop in NC 196 this season. Most of the rest is CC 37, which is also black-shank resistant. He also has a little K 326, which has no resistance to black shank at all, but he plants it for a reason.

In addition to producing high-quality leaf, K 326 holds its weight and quality in the field for an exceptional period of time after it reaches the point of optimum maturity.

That allows you to harvest more of a late crop with a given labor crew without having to hire extra workers.

“It will sit there and hold on the stalk and still not cure dark,” Mitchell said.

Mitchell has arranged things so that susceptibility to black shank wasn't really a liability. “I planted it in some new ground we recently cleared,” he said.

Since black shank is associated solely with tobacco production, there is not likely to be any black shank in soil that has never been in tobacco.

The same applies to burley, but that would make almost no difference for burley growers who plant KT 209. It's resistance to race zero blank shank is so high that it is for all practical purposes immune, and it's resistance to race one is eight out of 10.

That is the highest level of black shank resistance of any commercially available burley variety, said Danny Peek, Virginia Extension burley specialist.

“With many burley-growing areas now reporting the presence of race one black shank in combination with race zero, KT 209 is expected to provide good black shank tolerance.”

Note though that even though the resistance to black shank is relatively high in KT 209, it is not immune to race one, said Bob Pearce, Kentucky Extension tobacco specialist.

“In areas with heavy race one black shank pressure, fungicides are still recommended for KT 209.”

Heavy stalks

KT 209 and the other high-yielding burley varieties developed by the Kentucky-Tennessee breeding program have been a great help to burley growers.

But the size of these varieties can cause a management problem, said grower David Miller of Abingdon, Va.

“The 'KT' varieties are huge, and our labor has trouble getting it in the barn,” he said.

He has addressed the problem by re-adopting a traditional practice he had gotten away from — wilting his burley after cutting it to lower moisture weight.

“We used to just cut it and put it straight into the barn,” Miller said. “Now we try to leave it out in the field for three to four days to reduce the weight and get the sunburn out.”

Unfortunately for dark air-cured and fire-cured growers, no dark variety has black shank resistance comparable to the most resistant burley and flue-cured varieties.

“But with levels of race one black shank increasing throughout the dark tobacco region, varieties with at least some resistance to race one should be considered for use where black shank is known to exist,” said Andy Bailey, Kentucky-Tennessee Extension tobacco specialist.

“Fungicides are recommended with any dark tobacco variety transplanted into fields with a history of black shank.”

If you must grow tobacco in fields with significant black shank levels, consider growing a resistant burley variety instead of dark, he said.

Disease note:Blue mold appeared at one location in Connecticut and another in Massachusetts in July. Both outbreaks were on shade-grown tobacco in the Connecticut River Valley.

Earlier, there were several incidences near Lancaster, Pa. Spraying took place at all locations. Through Aug. 1, no economic loss had occurred at any of the locations.